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Li B.,University of Nebraska Medical Center | Ricordel I.,Institute National Of Police Scientifique | Schopfer L.M.,University of Nebraska Medical Center | Baud F.,University Paris Diderot | And 5 more authors.
Toxicological Sciences

Studies in mice and guinea pigs have shown that albumin is a new biomarker of organophosphorus toxicant (OP) and nerve agent exposure. Our goal was to determine whether OP-labeled albumin could be detected in the blood of humans exposed to OP. Blood from four OP-exposed patients was prepared for mass spectrometry analysis by digesting 0.010 ml of serum with pepsin and purifying the labeled albumin peptide by offline high performance liquid chromatography. Dimethoxyphosphate-labeled tyrosine 411 was identified in albumin peptides VRY411TKKVPQVSTPTL and LVRY411TKKVPQVSTPTL from two patients who had attempted suicide with dichlorvos. The butyrylcholinesterase activity in these serum samples was inhibited 80%. A third patient whose serum BChE activity was inhibited 8% by accidental inhalation of dichlorvos had undetectable levels of adduct on albumin. A fourth patient whose BChE activity was inhibited 60% by exposure to chlorpyrifos had no detectable adduct on albumin. This is the first report to demonstrate the presence of OP-labeled albumin in human patients. It is concluded that tyrosine 411 of human albumin is covalently modified in the serum of humans poisoned by dichlorvos and that the modification is detectable by mass spectrometry. The special reactivity of tyrosine 411 with OP suggests that other proteins may also be modified on tyrosine. Identification of other OP-modified proteins may lead to an understanding of neurotoxic symptoms that appear long after the initial OP exposure. © The Author 2010. Published by Oxford University Press on behalf of the Society of Toxicology. All rights reserved. For permissions, please email: journals.permissions@oxfordjournals.org. Source

Haned H.,University Claude Bernard Lyon 1 | Pene L.,Institute National Of Police Scientifique | Sauvage F.,University Claude Bernard Lyon 1 | Pontier D.,University Claude Bernard Lyon 1
Forensic Science International: Genetics

We propose to quantify the accuracy of a likelihood-based estimator that was recently proposed for the determination of the number of contributors to a DNA mixture, when genetic data alone is considered [H. Haned, L. Pène, J.R. Lobry, A.B. Dufour, D. Pontier, Estimating the number of contributors to forensic DNA mixtures: does maximum likelihood perform better than maximum allele count? J. Forensic Sci., in press]. Using Bayes' theorem, we derive a formula for the calculation of the predictive value (PV) of the likelihood-based estimator. The PV gives the probability that a DNA stain contains the DNAs of i people given that the maximum likelihood estimator gave an estimate of i contributors for this stain. We illustrate the PV calculations for two different types of DNA evidence: traces and body fluids. The PV varied according to the number of contributors involved in the DNA stain. Setting the maximum number of possible contributors to five, the lowest predictive values were scored for five-person mixtures with a minimum value of 0.26 for traces, but values were always above 0.94 for stains comprising one, two or three contributors, for both traces and body fluids. Values remained relatively high for four-person mixtures with a minimum value of 0.69. These findings confirm that likelihood-maximization is a powerful approach for the determination of the number of contributors to forensic DNA mixtures. © 2010 Elsevier Ireland Ltd. All rights reserved. Source

In France, according to the official statistics of the Home Office, we count in full year more than 100.000 hitand-run car offences after accident (135.147 in 2008 that is approximately 25% of the noticed road offences, representing the second source of offences after the driving under the influence of alcohol. To identify the runaway vehicle the Physics-Chemistry sections of the French laboratories of scientific police of the INPS (National Institute of Scientific Police) use various techniques of chemical analysis, as the infrared spectrometry. After analyses, the results are compared with those obtained for present motor vehicles in database of the automotive paints. This database arises from a fruitful collaboration which began in the middle of 1990s, between various European scientific laboratories of police. The implement of this ?chemical recording information? on the automotive paints is proving to be of a precious help in the ?demonstration of the truth". Source

Briant E.,Institute National Of Police Scientifique
Actualite Chimique

The identification of persons for judicial purposes has been a great step forward with the establishment of anthropometric files by Alphonse Bertillon in late XIXth century. The discovery of fingerprints as individual mark allows Bertillon to create a schematic fingerprints database. The automated database will be created in France in 1987 ("Fichier automatisé des empreintes digitales", FAED). With the discovery of DNA in 1953 and the development of techniques for DNA analysis, techniques for identification evolve. Eleven years after the FAED, the national automated database of DNA fingerprint (FNAEG) is created in order to record genetic profiles of persons involved in sexual crimes. The Perben law of 2004, allowing the extension of crimes leading to the establishment of DNA profiles, increases the number of genetic profiles registered in the FNAEG. Today more than 1 240 464 profiles are registered and 58 378 comparisons have been made. This article aims to illustrate the implication of chemistry in the determination of a revolutionary scientific proof one century after the fingerprints: the DNA profiling. Source

Haned H.,CNRS Biometry and Evolutionary Biology Laboratory | Pene L.,Institute National Of Police Scientifique | Lobry J.R.,CNRS Biometry and Evolutionary Biology Laboratory | Dufour A.B.,CNRS Biometry and Evolutionary Biology Laboratory | Pontier D.,CNRS Biometry and Evolutionary Biology Laboratory
Journal of Forensic Sciences

Determining the number of contributors to a forensic DNA mixture using maximum allele count is a common practice in many forensic laboratories. In this paper, we compare this method to a maximum likelihood estimator, previously proposed by Egeland et al., that we extend to the cases of multiallelic loci and population subdivision. We compared both methods' efficiency for identifying mixtures of two to five individuals in the case of uncertainty about the population allele frequencies and partial profiles. The proportion of correctly resolved mixtures was >90% for both estimators for two- and three-person mixtures, while likelihood maximization yielded success rates 2- to 15-fold higher for four- and five-person mixtures. Comparable results were obtained in the cases of uncertain allele frequencies and partial profiles. Our results support the use of the maximum likelihood estimator to report the number of contributors when dealing with complex DNA mixtures. © 2010 American Academy of Forensic Sciences. Source

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